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A tall mason jar of sourdough starter with some overflowing. A small bowl of flour and a pink linen behind it.

Sourdough Starter

All you need is flour and water to make this Sourdough Starter. It's so easy to make it from scratch with this foolproof recipe!
Course bread
Cuisine American
Prep Time 5 days
Total Time 5 days
Servings 0.5 cup


  • Scale (optional)
  • Pint- or quart-sized glass container


For the Starter:

  • ½ cup whole wheat flour (60g)
  • ¼ cup filtered water (60g)

For Each Feeding:

  • ½ cup unbleached all-purpose flour (60g)
  • ¼ cup filtered water (60g)


For the Starter:

  • Day 1: In a clean glass jar (at least a pint or larger in size), combine the whole wheat flour and water. Stir together until the flour is fully combined. It should be the consistency of a paste or thick batter. If it’s dough-like, thin with a bit more water.
  • Cover the container loosely with the lid and let the jar sit in a warm spot (75-80F) for 24 hours.
  • Day 2: Check the starter for any bubbles that have formed on top. If it doesn’t appear bubbly, let the starter sit for another 12 to 24 hours or until you see signs of bubbles. When you do see bubbles or if a greyish liquid has formed on top, continue on with feeding. (This timing will depend on the ambient temperature where the starter is sitting. You may not see any activity within the first 24 hours if it’s cool.)

For Each Feeding:

  • Discard half of the starter, keeping about 60g in the container. Add the all-purpose flour and water to the container, and stir until well combined. Mark the level of the mixture on the side of the container with a rubber band or piece of tape. Loosely cover and let it rest in a warm spot for another 24 hours.
  • Day 3: Check the starter. It should be very bubbly and risen, almost doubling in volume. If you do not see much activity or the starter hasn’t increased in volume, continue to let the mixture sit until it does. (This could take another 24 hours.)
  • Once risen, discard half of the starter and feed again with the same amounts of flour and water. Loosely cover and let the starter sit until it has doubled in size. This could be anywhere from 6 to 24 hours.
  • Day 4/5: Continue discarding and feeding the starter 2 more times after it doubles in volume each time. (You will be creating a bit of discard or waste in this initial phase, but it’s worth it! Once your starter is healthy and active, you can use the discard in other recipes.)
  • After the final feeding and rise, your starter is ready to use! You can follow my recipe for homemade Sourdough Bread to put it to use.
  • To store your starter long-term, keep it refrigerated so it stays healthy. Before storing, discard and feed one more time. Let the starter sit in a warm spot just until it starts to rise (about 2 hours), then cover tightly and refrigerate. Feed it by repeating the same process of discarding and adding flour and water once every 2 weeks to keep the starter healthy. The cold will slow the yeast down so that they feed on the flour more slowly. When ready to bake again, discard and feed as normal. Let the starter sit in a warm place until doubled in size. Use as directed in the recipe.


  • Look for signs that your starter is hungry. Typically, a starter doubling in volume means the yeast is almost at its tipping point of running out of food (or fresh flour). When the starter has doubled in volume but then starts to shrink back down, this indicates it’s “hungry” and running out of fresh flour. This is an excellent time to feed it! Make sure you don’t wait for more than a few hours at this point, or the yeast will start dying. You can also overfeed a starter, meaning you don’t allow enough time between feeding for the yeast to grow. Make sure to only feed after it’s almost doubled in volume or has begun shrinking again.
  • A sourdough starter stored in the fridge or left on the counter for too long can form a clear or greyish liquid on top. The liquid is sometimes called “hooch” and is actually alcohol that forms when the yeast finishes feeding on the fresh flour. You can pour this off or just stir it back into the starter before feeding.
  • Your starter should smell sweet and tangy. If the starter smells foul, it could be due to using an unclean jar or bad bacteria was somehow introduced to the starter. If this happens, you will have to start over.
  • If you see discoloring or mold on the surface of your starter, discard it and start again.
  • Make sure you have fresh flour. Your flour should have a pleasant sweet smell. If the flour is stale, I recommend replacing it.
  • Warm water is excellent for feeding the starter, giving it a little boost. However, hot water can damage or kill the cultures in the starter.
  • I highly recommend using a scale as the feedings require equal parts water and flour. A scale will ensure accuracy and consistency.
  • If you have a cold kitchen, or if it’s winter, you can create a warm spot for your starter by placing it inside the oven with the light on. Only turn on the light and not the oven! The heat from the light will create a warm environment for the starter.
  • A rubber band or a piece of masking tape around the jar is a great way to keep track of the starter’s growth. I like using a rubber band as you can simply roll it up and down the jar, but masking tape is great if you need to mark down notes and timing.
  • I highly recommend using a glass jar for the starter. Avoid contact with reactive metals like copper or aluminum, as the acid in the starter can react with the metal.